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A CMOS phase-shift oscillator that uses a phase shift in the conduction of heat is proposed. The oscillator consists of an inverting amplifier and a feedback thermal filter that are integrated on a silicon chip. The thermal filter consists of a polysilicon heater and a MOSFET thermosensor separated from each other by a S_iO₂ heat-conducting layer.¹ An input signal for the filter travels from the heater to the thermosensor through the S_iO₂ layer in the form of heat. The filter accepts the output of the inverting amplifier, produces a phase shift due to the heat conduction, and returns a 180°-shifted feedback signal to the amplifier. The oscillator produces oscillation at a specific frequency determined by the dimensions of the filter and the thermal conductivity and specific heat of Si and S_iO₂.

Tragically more babies fall victim to sudden infant death syndrome than the combined numbers of respiratory ailment, heart disease and cancer deaths. The cases take place for those babies who were under one year of age and especially often for those babies who were in the age around two to four month old. Despite extensive research, the exact cause of sudden infant death syndrome is still not known. Shockingly, it can even happen to apparently healthy babies left alone for just a little while. The conventional infant apnea monitor adopts disposable electrodes as sensors for apnea detection and thus inducing the problems of skin irritated or other hazards. To tackle these shortcomings, we develop a non-attached type apnea monitor. The device monitors the temperature of the breathing airflow by means of thermo sensors. These airflow frequencies linking with respiratory rates are indicated on the monitor. There is absolutely no contact with the babies' skin, avoiding the possibilities of any skin irritations. The system detects temperature changes induced by breathing and analyzes the breathing frequency changes displayed with both LED array and computer monitor. The data are collected and analyzed simultaneously by a personal computer, which can link to the central nursery room. The device provides a convenient way for pediatricians or nurses to detect abnormal respiratory frequency in real time so they can handle any emergency and gives the necessary treatment immediately. Ten clinic cases have been analyzed and presented. Function validation of the device, on the other hand, is performed as well.

The conventional apnea monitor adopts disposable electrodes as sensors for apnea detection and thus inducing the problems of skin irritation and other side effects. To tackle these shortcomings, we develop a non-attached type of apnea monitor. The device monitors the temperature of the breathing airflow by means of thermo sensors. These airflow frequencies linked with respiratory rates are indicated on the monitor. There is absolutely no contact with the patients' skin, avoiding the possibilities of any skin irritation. The system detects temperature changes induced by breathing and analyzes the breathing frequency changes displayed by both LED array and computer monitor. The data are collected and analyzed simultaneously by a personal computer, which can link to the central nursery room. The device provides a convenient way for family or nurses to detect abnormal respiratory rate in real time so they can handle any emergency and give the necessary treatment immediately for those patients in persistent vegetative state. Clinic application is presented and function validation of the device, on the other hand, is performed as well.